摘要：
The Antique Comedians of Malidinesia prefer comedies to tragedies. Unfortunately, most of the ancient plays are tragedies. Therefore the dramatic advi 阅读全文
摘要：
In Africa there is a very special species of bee. Every year, the female bees of such species give birth to one male bee, while the male bees give bir 阅读全文
摘要：
In 1949 the Indian mathematician D.R. Kaprekar discovered a class of numbers called self-numbers. For any positive integer n, define d(n) to be n plus 阅读全文